Facing the fan, route the fan wiring through the left hole in part #332, the hot end wiring will also feed through this same hole.

Note - Depending on the hot end that you receive (ceramic or cartridge) you may want to wait to put the fan mount on later in your build (photo #2). The cartridge hot end is much larger and will not fit through the slot in the red box. The ceramic will fit through if you feed the lead wires through first.

this assembly sandwiches the y- and z-axis bearings, supports the threaded rod nut, and provides the y-axis motor mount

NOTE: the y-axis endstop switch is already attached to 321 (with the "mouth" opening up the edge of that part-- in the yellow box). This switch can only be correctly-- and most easily-- installed when the stack is not fastened together.

Note - look at the two sides of the extruder motor connector, one side is completely solid black and the other shows the wire connectors. make sure the cable is connected with wire connectors facing into the board

leave hotend thermistor cable disconnected from the Printrboard for now

this assembled kit is now ready for testing, calibration, and printing

NOTE: additional guides for the electronics installation and extruder mounting are in the works. Please see the http://printrbot.com/support/ for updated guides and additional technical support documents. Thank you.

Just finished building so thought I'd post these notes to help you and others.

Time: Took me many hours longer than the 1-2 hours to build the main structure. Most of this was fettling parts, going back over bits and checking hadn't overtightened anything critical. If i built another from scratch, probably three hours for the main, an hour for the extruder and an hour to fit / bunch all the wiring in.

Difficulty: If you can assemble model airplane kits form wood then you can build this. You need to be aware that this is NOT a lego kit. It needs careful informed assembly and often you have to research to get some bits right.

The youtube videos are still gone. I have submitted a support ticket and hope that they will get them back up soon.

In the meantime, it is possible to assemble the kit just based off these instructions. This is what I am doing and I will post clarification comments about things as I figure them out. (Presumably many clarifications were not needed earlier when the videos were still up.)

On the Bill of Materials, there is only a single 1 1/4" bolt mentioned, and it's needed for the Extruder. I do not have any in the kit. I used 1" bolts at the time since they fit pretty nicely, however now I realized that I need those for a later step (building the extruder).

So, does the teeth of the belt need to make contact with the gear on the motor? The picture and the video makes it looks like only the back side of the belt needs to make contact with te barrings....but then the motor won't make the table move of course.

I had trouble with understanding this too. Both bearings touch the belt, with the gear in the middle. The belt enters from the right side, goes in between the bearing and the motor (with the teeth touching the gear), follows the gear, and goes in-between the gear and the second bearing. So it makes a ‾U‾ shape.

I came up 1 X 1" short in the end. I also believe the end stop adjustment screw is better off using a 1 1/2, and that would have made up the missing 1". Perhaps the part inventory changed correctly, but the instructions are not up to date?

The photo of the motor in step 41 looks different than the large motor that you get in the kit and that you're supposed to use for this step. The motor shown in the photos in step 41 and 42 (especially if you look at the wires in the step 42 photo) is of the smaller motor, which you shouldn't be using in this step.

You are correct. The ceramic hot end, which you received, has black insulation on the power leads. The cartridge hot end, which is shown in the guide, has red insulation on the power leads. Sorry for the confusion.

If you look on the control board there is a two pin male connector on the right hand side above where you plugged in the hotend thermistor cable in step 68. It says "fan" on the board just beneath it, I'm gonna try plugging it in there and hope that it works!

Connect the thermistor to the board in step 68. It can be difficult to fit the board into the box of the Jr if the thermistor cable is connected to the board. We connect it once the board is fitted in the box.